JP2009293484A - Dynamic valve device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dynamic valve device for an internal combustion engine equipped with a plurality of rocker arms arranged adjacently using a common swinging axis, a plurality of cams installed on a cam shaft in such a way as mating with respective rocker arms, and a coupling changeover means for changing the operating mode of an engine valve by changing over coupling and uncoupling of the combination of rocker arms, capable of enhancing the degree of flexibility for the layout of an oil path formed in the rocker arms. <P>SOLUTION: The coupling changeover means 23 is equipped with a plurality of coupling pins 41 and 42 to change over coupling and uncoupling of adjoining rocker arms 18, 19, 20; 20, 21 in accordance with the action of a hydraulic force, wherein in at least one coupling pin 42, the oil path 89 leading to an oil pressure chamber 52 facing the end of the coupling pin 42 is formed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention switches a combination of a plurality of rocker arms arranged adjacent to each other with a common swing axis, a plurality of cams provided on a camshaft corresponding to each of the rocker arms, and a connection and release of the rocker arms. The present invention relates to a valve operating apparatus for an internal combustion engine comprising a connection switching means capable of changing the operation mode of the engine valve.

A plurality of rocker arms respectively corresponding to a plurality of cams provided on the camshaft are arranged adjacent to each other with a common swing axis, and the operation mode of the engine valve is changed by switching the combination of connection and release of each rocker arm with a connection switching means. A valve operating apparatus for an internal combustion engine that is changed is already known from, for example, Japanese Patent Application Laid-Open No. H10-228707.
JP-A-7-180518

  However, the one disclosed in the above-mentioned Patent Document 1 is formed in the rocker arm with one end of the engagement switching pin that constitutes a part of the connection switching means facing the connection and release of the connection between the adjacent rocker arms. An oil passage that guides hydraulic oil to the hydraulic chamber is provided in the rocker arm in which the hydraulic chamber is formed, and the oil passage must be provided in the rocker arm at a position corresponding to the hydraulic chamber. The degree of freedom will be narrowed.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a valve operating apparatus for an internal combustion engine with an increased degree of freedom in arrangement of an oil passage provided in a rocker arm.

  In order to achieve the above object, the present invention provides a plurality of rocker arms arranged adjacent to each other with a common swing axis, a plurality of cams provided on a camshaft individually corresponding to the rocker arms, and a connection between the rocker arms. And a connection switching means capable of changing the operation mode of the engine valve by switching the combination of the connection release, the connection changeover means for connecting and releasing the adjacent rocker arms with the hydraulic pressure. A plurality of connecting pins that switch depending on the action are provided, and an oil passage that leads to a hydraulic chamber that faces the end of the connecting pin is formed in at least one of the connecting pins.

  The intake valve 13 of the embodiment corresponds to the engine valve of the present invention, and the drive rocker arm 18, the first free rocker arm 19, the second free rocker arm 20, and the third free rocker arm 21 of the embodiment correspond to the rocker arm of the present invention. The pause cam 26, the Atkinson cycle cam 27, the medium load range normal cycle cam 28, and the high load range normal cycle cam 29 of the embodiment correspond to the cam of the present invention, and the second hydraulic chamber 52 of the embodiment is the hydraulic chamber of the present invention. Corresponding to

  According to the above configuration of the present invention, since the oil passage leading to the hydraulic chamber is formed in at least one connecting pin, the oil passage provided on the rocker arm side and leading to the oil passage is within the movement stroke of the connecting pin. The degree of freedom in the arrangement of the oil passages provided in the rocker arm while optimizing the configuration such as the position and shape of each rocker arm constituting the valve operating system, the interface between those rocker arms and each connecting pin, etc. Can be increased.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

  1 to 7 show an embodiment of the present invention, FIG. 1 is a longitudinal side view of a valve operating apparatus, a sectional view taken along line 1-1 of FIG. 2, and FIG. FIG. 3 is a cross-sectional view taken along line 2-2 in FIG. 1, FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 1 in the resting operation mode, and FIG. 5 is a cross-sectional view corresponding to FIG. 2 in the high-load normal cycle operation mode, FIG. 6 is a cross-sectional view corresponding to FIG. 2 in the medium-load normal cycle operation mode, and FIG. 7 is the Atkinson cycle operation mode. It is sectional drawing corresponding to FIG.

  First, in FIG. 1, a valve shaft 13 a of an intake valve 13, which is an engine valve that opens and closes a pair of intake valve ports 12 provided in a cylinder head 11 of an internal combustion engine, is a guide cylinder 14 provided in the cylinder head 11. The intake valves 13 are slidably fitted to the retainer 15 provided at the upper end of the valve shaft 13a protruding from the guide cylinder 14 and the valve spring 16 provided between the cylinder heads 11. Is biased in the valve closing direction.

  2 and 3 together, the valve operating device 17 for driving the intake valves 13 to open and close includes a drive rocker arm 18 that is linked and connected in common to the intake valves 13, and the both intake valves. 13... First, second and third free rocker arms 19, 20, 21 which can be free with respect to the camshaft 22 for swinging and driving the first to third free rocker arms 19 to 21, and the drive rocker arm 18. And connection switching means 23 that can change the operation mode of the intake valves 13 by switching the combination of connection and connection release of the first to third free rocker arms 19 to 21.

  The drive rocker arm 18 and the first to third free rocker arms 19 to 21 are swingable around a common swing axis, and one end portions of the drive rocker arm 18 and the first to third free rocker arms 19 to 21 are The rocker shaft 24 is swingably supported by a common rocker shaft 24. The rocker shaft 24 has an axis parallel to the camshaft 22 and is disposed below the camshaft 22.

  The drive rocker arm 18 and the first to third free rocker arms 19 to 21 are disposed adjacent to each other in the axial direction of the rocker shaft 24, and the first and second free rocker arms 19 and 20 are disposed on both sides of the drive rocker arm 18. The third free rocker arm 21 is disposed at a position sandwiching the second free rocker arm 20 between the drive rocker arm 18 and the third free rocker arm 21.

  The other end of the drive rocker arm 18 is integrally provided with connecting arm portions 18a extending on both sides along the axial direction of the rocker shaft 24, and the intake valves 13 are connected to both ends of the connecting arm portion 18a. Tappet screws 25 and 25 that are in contact with the upper ends of the valve shafts 13a are screwed together so that the forward / backward position can be adjusted.

  The camshaft 22 includes a pause cam 26 corresponding to the drive rocker arm 18, an Atkinson cycle cam 27 corresponding to the first free rocker arm 19, an intermediate load range normal cycle cam 28 corresponding to the second free rocker arm 20, A high load range normal cycle cam 29 corresponding to the three-free rocker arm 21 is provided.

  A cam slipper 30 capable of sliding contact with the rest cam 26 is provided at the upper end of the other end of the drive rocker arm 18. A cylindrical first shaft member 31 is fitted and fixed to the other end of the first free rocker arm 19 so that the outer end surface is connected to the side surface of the first rocker arm 19 on the side of the drive rocker arm 18. The first roller 32 that is in rolling contact with the Atkinson cycle cam 27 is rotatably supported by the first shaft member 31 via the first needle bearing 33. On the other end side of the second free rocker arm 20, a cylindrical second shaft member 34 is fitted and fixed so that the outer end surface is connected to the side surface of the drive rocker arm 18 side of the second free rocker arm 20. The second roller 35 that can be brought into rolling contact with the intermediate load range normal cycle cam 28 is rotatably supported by the second shaft member 34 via the second needle bearing 36. Further, on the other end side of the third free rocker arm 21, a cylindrical third shaft member 37 is fitted to the side surface of the third free rocker arm 21 on the second free rocker arm 20 side so that the outer end surface is flush with the other side. The third roller 38, which is fixed and is in rolling contact with the high load region normal cycle cam 29, is rotatably supported by the third shaft member 37 via the third needle bearing 39.

  The connection switching means 23 can switch the combination of connection and release of the adjacent rocker arms 18 to 21 according to the action of the oil pressure. In this embodiment, the drive rocker arm 18 is switched to the first to third free rocker arms 19. To 21, a state where the drive rocker arm 18 is connected to the first free rocker arm 19, a state where the drive rocker arm 18 is connected to the second free rocker arm 20, and the second and third states of the drive rocker arm 18. The state connected to the rocker arms 20 and 21 can be switched.

  The pause cam 26 has an outer diameter corresponding to the base circle of the Atkinson cycle cam 27, the medium load range normal cycle cam 28, and the high load range normal cycle cam 29, and is circular with the axis of the camshaft 22 as the center. If the valve operating device 17 of the specific cylinder is not connected to the drive rocker arm 18 in the low load region of the engine, the intake valve 13 of the specific cylinder is ... 4 corresponds to the cam profile of the rest cam 26, the valve lift amount of the intake valves 13 is "0" as shown in FIG. 4, and the intake valves 13 are closed.

  In a state where the drive rocker arm 18 is connected to the first free rocker arm 19, the operation mode of the intake valves 13... Corresponds to the cam profile of the Atkinson cycle cam 27, and the intake valves 13 are opened and closed as shown in FIG. To do. The Atkinson cycle using the Atkinson cycle cam 27 can improve the efficiency by reducing the pumping loss under a certain condition and can reduce the fuel consumption. There is an operating region in which there is a decrease in efficiency, and it is necessary to avoid a decrease in efficiency in such an operating region. Therefore, a medium load normal cycle operation mode in which the drive rocker arm 18 is connected to the second free rocker arm 20 and a high load normal cycle operation mode in which the drive rocker arm 18 is connected to the second and third free rocker arms 20 and 21 are prepared. Yes. Thus, when the drive rocker arm 18 is connected to the second free rocker arm 20, the operation mode of the intake valves 13 ... corresponds to the cam profile of the medium load range normal cycle cam 28, and the intake valves 13 ... are shown in FIG. When the drive rocker arm 18 is connected to the second and third free rocker arms 21 as shown in FIG. 6, the operation mode of the intake valves 13... Corresponds to the cam profile of the high load range normal cycle cam 29. As shown in FIG. 4, the intake valves 13... Open and close with a valve lift amount and an opening angle larger than those in the medium load normal cycle operation mode.

  By the way, the cam profile of the high load range normal cycle cam 29 has a shape including the cam profile of the medium load range normal cycle cam 28, so that the third free rocker arm 21 and the second free rocker arm 20 are sandwiched between the second free rocker arm 20. Even when connected to the drive rocker arm 18, the intake valves 13 can be opened and closed with characteristics corresponding to the cam profile of the high load range normal cycle cam 29 without being affected by the normal load range normal cycle cam 28. On the other hand, the Atkinson cycle cam 27 has a cam profile that intersects with the cam profiles of the medium load range normal cycle cam 28 and the high load range normal cycle cam 29, as shown in FIG. The third free rocker arm 20, 21 is provided on the camshaft 22 at a position corresponding to the first free rocker arm 19 positioned on the opposite side with respect to the drive rocker arm 18, and only the first free rocker arm 19 is connected to the drive rocker arm 18. In the operation state of the Atkinson cycle, the middle load range normal cycle cam 28 and the high load range normal cycle cam 29 are prevented from being affected.

  The connection switching means 23 includes a plurality of connection pins. In this embodiment, the drive rocker arm 18 is connected to the first free rocker arm 19 but the connection with the second free rocker arm 20 is released, and the drive rocker arm. 18 is connected to the second free rocker arm 20, but the first connection pin 41 is switchable to release the connection with the first free rocker arm 19, and the second and third free rocker arms 20 and 21 are connected and disconnected. And a switchable second connecting pin 42.

  The first connecting pin 41 has a length corresponding to the distance between both side surfaces of the drive rocker arm 18 and is formed in a columnar shape, and opens to both side surfaces of the drive rocker arm 18 so as to open. Is slidably fitted in a first sliding hole 43 provided in the first. Thus, the first sliding hole 43 has a first shaft when the cam slipper 30 of the drive rocker arm 18 is in contact with the rest cam 26 and the first roller 32 of the first free rocker arm 19 is in rolling contact with the Atkinson cycle cam 27. The drive rocker arm 18 is provided so as to be coaxial with the member 31.

  A first fitting hole 44 into which one end of the first connecting pin 41 is fitted to the end of the first rocker arm 18 on the side of the drive rocker arm 18 fitted and fixed to the first free rocker arm 19, and a first fitting. An annular first restricting surface 45 that abuts one end face of the first connecting pin 41 fitted in the joint hole 44 is provided, and the first connecting pin is brought into contact with the first restricting face 45. When 41 is fitted into the first fitting hole 44, the drive rocker arm 18 released from the connection with the second free rocker arm 20 is connected to the first free rocker arm 19.

  A second fitting hole 46 through which the other end of the first connecting pin 41 can be fitted is provided at the end of the second shaft member 34 fitted and fixed to the second free rocker arm 20 on the drive rocker arm 18 side. The second fit is made in a state where the cam slipper 30 of the drive rocker arm 18 is in contact with the rest cam 26 and the second roller 35 of the second free rocker arm 20 is in rolling contact with the base circle of the normal load cam 28. The joint hole 46 is coaxial with the first sliding hole 43. The second shaft member 34 and the second free rocker arm 20 have a diameter smaller than that of the second fitting hole 46 and are coaxially connected to the second fitting hole 46, and the side surface of the second free rocker arm 20 on the third free rocker arm 21 side. A second sliding hole 47 is provided, and an annular second regulating surface 48 facing the third free rocker arm 21 is formed between the second fitting hole 46 and the second sliding hole 47. The Moreover, the second sliding hole 47 is formed to have a larger diameter than the first sliding hole 43.

  The second connecting pin 42 has a length such that the other end surface is flush with the third free rocker arm 21 side surface of the second free rocker arm 20 when one end is brought into contact with the second restriction surface 48. The sliding hole 47 is slidably fitted. Thus, the axial length of the second fitting hole 46 is set to be the same as the axial length of the first fitting hole 44 in the first shaft member 31. In a state where the end side is fitted in the second fitting hole 46 until it abuts on one end of the second connecting pin 42 in a state where one end is in contact with the second regulating surface 48, one end portion of the first connecting pin 41 Is disengaged from the first fitting hole 44 of the first free rocker arm 19, and in this state, the drive rocker arm 18 is connected to the second free rocker arm 20, but is disconnected from the first free rocker arm 19. is there.

  A third fitting hole 49 for fitting the other end of the second connecting pin 42 to the second free rocker arm 20 side end of the third shaft member 37 fitted and fixed to the third free rocker arm 21; An annular third restricting surface 50 that abuts the other end surface of the second connecting pin 42 fitted into the third fitting hole 49 is provided, and the second restricting surface 50 abuts the other end surface. The second free rocker arm 20 is connected to the third free rocker arm 21 by fitting the two connecting pins 42 into the third fitting hole 49.

  The first shaft member 31 and the drive rocker arm 18 are formed with a first hydraulic chamber 51 that faces one end portion of the first connection pin 41, and the second shaft member 34 and the second free rocker arm 20 are provided with the first connection pin 41. The second hydraulic chamber 52 that faces the other end and one end of the second connecting pin 42 is restricted, and the second end of the second connecting pin 42 faces the third shaft member 37 and the third free rocker arm 21. Three hydraulic chambers 53 are formed. Thus, the second sliding hole 47 in which the second connecting pin 42 is slidably fitted has a larger diameter than the first sliding hole 43 in which the first connecting pin 41 is slidably fitted. Therefore, the pressure receiving area of the second connecting pin 42 facing the third hydraulic chamber 53 is larger than the pressure receiving area of the first connecting pin 41 facing the first hydraulic chamber 51.

  Thus, an annular first seal member 54 surrounding the first hydraulic chamber 51 is mounted on the side surface of the drive rocker arm 18 on the first free rocker arm 19 side so as to be in sliding contact with the first free rocker arm 19. An annular second seal member 55 surrounding the second hydraulic chamber 52 is mounted on the side surface of the second free rocker arm 20 so as to be in sliding contact with the second free rocker arm 20, and the side surface of the second free rocker arm 20 on the third free rocker arm 21 side. An annular third seal member 56 that surrounds the third hydraulic chamber 53 is attached.

  Incidentally, an annular engagement groove 57 is provided on the outer periphery of the axially central portion of the first connecting pin 41. On the other hand, the drive rocker arm 18 has a support hole 58 into which the rocker shaft 24 is fitted, and a third slide in which one end is opened at the inner surface of the support hole 58 and the other end is opened at the inner surface of the first slide hole 43. The hole 59 is provided so as to have an axis perpendicular to the first connecting pin 41, and the piston 60 is slidably fitted into the third sliding hole 59. Thus, a fourth hydraulic chamber 61 that faces one end of the piston 60 is formed in the drive rocker arm 18 and the rocker shaft 24, and a piston rod 62 extending in the opposite direction to the fourth hydraulic chamber 61 is coaxially and integrally formed with the piston 60. And an engaging pin 62 a that can be engaged with the engaging groove 57 is provided at the tip of the piston rod 62. Moreover, between the drive rocker arm 18 and the piston 60, a spring 63 for biasing the piston 60 is contracted on the side of reducing the volume of the fourth hydraulic chamber 61, and the hydraulic pressure of the fourth hydraulic chamber 61 is released. Then, the piston 60 is in a position retracted from the engagement groove 57 to a position where the engagement pin 62a is released, and in this state, the axial movement of the first connection pin 41 is allowed.

  Referring again to FIG. 1, four cylindrical first to fourth partition members 64, 65, 66, and 67 are fitted and fixed in the rocker shaft 24. 1 oil passage 68 is formed, a second oil passage 69 is formed in the second partition member 65, a third oil passage 70 is formed in the third partition member 66, and in the fourth partition member 67. A fourth oil passage 71 is formed.

  On the other hand, in the crankcase 72 of the internal combustion engine, a pump 73 that pumps up the hydraulic oil stored in the lower part of the crankcase 72 is housed, and a hydraulic oil supply path 74 connected to the discharge port of the pump 73 is The first to fourth oil passages 68 to 71 are connected via a hydraulic pressure switching unit 75.

  The hydraulic pressure switching unit 75 includes first and second rotary valves 76 and 77. The first rotary valve 76 includes a state where both the first and second oil passages 68 and 69 are disconnected from the hydraulic oil supply oil passage 74, a state where the first oil passage 68 is communicated with the hydraulic oil supply oil passage 74, The state where the two oil passages 69 communicate with the hydraulic oil supply oil passage 74 can be switched, and the second rotary valve 77 blocks both the third and fourth oil passages 70 and 71 from the hydraulic oil supply oil passage 74. The state can be switched between a state in which the third oil passage 70 communicates with the hydraulic oil supply oil passage 74 and a state in which the fourth oil passage 71 communicates with the hydraulic oil supply oil passage 74.

  2, the first free rocker arm 19, the second free rocker arm 20, the third free rocker arm 21, and the drive rocker arm 18 include first to fourth annular recesses 81, 82, 83, which surround the rocker shaft 24. 84 is provided, and the fourth annular recess 84 communicates with the fourth hydraulic chamber 61.

  The rocker shaft 24 and the first partition member 64 are provided with a communication passage 85 that allows the first annular recess 81 to communicate with the first oil passage 68, and the first free rocker arm 19 and the first shaft member 31 have the communication passage. An oil passage 86 is provided for communicating 85 with the first hydraulic chamber 51, and the first oil passage 68 communicates with the first hydraulic chamber 51.

  The rocker shaft 24 and the second partition member 65 are provided with a communication passage 87 that allows the second annular recess 82 to communicate with the second oil passage 69, and the second free rocker arm 20 includes an oil passage that communicates with the communication passage 87. 88 is provided, and an oil passage 89 bent in an L shape is formed in the second connecting pin 42 so that the oil passage 88 communicates with the second hydraulic chamber 51, and the second oil passage 69 is connected to the second oil passage 69. 2 communicates with the hydraulic chamber 52. Thus, the connection switching means 23 includes the first and second connection pins 41 and 42, but the second hydraulic pressure that allows the other end of the first connection pin 41 and the one end of the second connection pin 42 to face each other. An oil passage 89 communicating with the chamber 52 is formed in the second connecting pin 42.

  The rocker shaft 24 and the third partition member 66 are provided with a communication passage 90 that allows the third annular recess 83 to communicate with the third oil passage 70, and the communication passage 90 is provided to the third free rocker arm 21 and the third shaft member 37. Is connected to the third hydraulic chamber 53, and the third oil passage 70 communicates with the third hydraulic chamber 53.

  Further, the rocker shaft 24 and the fourth partition member 67 are provided with a communication passage 92 that allows the fourth annular recess 84 to communicate with the fourth oil passage 71, and the fourth oil passage 71 communicates with the fourth hydraulic chamber 61.

  In such a connection switching means 23, in the high load range normal cycle of the engine, as shown in FIG. 5, the first hydraulic pin 51 is pressed against the second free rocker arm 20 side by applying hydraulic pressure to the first hydraulic chamber 51. . Then, the first connecting pin 41 is fitted into the second fitting hole 46 while releasing the fitting with the first fitting hole 44 and pressing the second connecting pin 42. As a result, the drive rocker arm 18 released from the connection with the first free rocker arm 19 is connected to the second free rocker arm 20 via the first connection pin 41. In addition, the second connecting pin 42 pushed by the first connecting pin 41 is fitted into the third fitting hole 53 of the third free rocker arm 21 with one end fitted to the first sliding hole 43 of the second free rocker arm 20. The second and third free rocker arms 20 and 21 are connected via the second connecting pin 42. That is, the drive rocker arm 18 is connected to both the second and third rocker arms 20 and 21, and the drive rocker arm 18 swings together with the third free rocker arm 21 that swings following the high load range normal cycle cam 29. The intake valves 13 are opened and closed in an operating manner corresponding to the cam profile of the high load range normal cycle cam 29.

  When switching from the high load range normal cycle to the medium load range normal cycle, the hydraulic pressure is applied to the third hydraulic chamber 53 while the hydraulic pressure is applied to the first hydraulic chamber 51, as shown in FIG. Then, since the pressure receiving area of the second connecting pin 42 facing the third hydraulic chamber 53 is larger than the pressure receiving area of the first connecting pin 41 facing the first hydraulic chamber 51, the second connecting pin 42 is connected to the first connecting pin 41 side. The hydraulic pressure that pushes the first connecting pin 41 becomes larger than the hydraulic pressure that pushes the first connecting pin 41 toward the second connecting pin 42, and the second connecting pin 42 pushes the first connecting pin 41 until it abuts against the second regulating surface 48. It will be. In this state, the connection of the second and third free rocker arms 20 and 21 by the second connection pin 42 is released, and the drive rocker arm 18 is connected to the second free rocker arm 20 by the first connection pin 41. That is, the drive rocker arm 18 swings with the second free rocker arm 20 that swings following the medium load range normal cycle cam 28, and the intake valve 13... Operates according to the cam profile of the medium load range normal cycle cam 28. Opens and closes.

  When switching from the medium load range normal cycle to the Atkinson cycle, as shown in FIG. 7, the hydraulic pressure in the first hydraulic chamber 51 is released, and the hydraulic pressure is applied to the second and third hydraulic chambers 52 and 53. Then, the second connecting pin 42 remains in contact with the second restricting surface 48, the first and second free rocker arms 20 and 21 are in a disconnected state, and the first connecting pin 41 is connected to the second hydraulic chamber 52. The drive rocker arm 18 is connected to the first free rocker arm 19 via the first connection pin 41 so that one end is fitted into the first fitting hole 44 by hydraulic pressure. Become. That is, the drive rocker arm 18 swings with the first free rocker arm 19 that swings in accordance with the Atkinson cycle cam 27, and the intake valves 13 open and close in an operating manner according to the cam profile of the Atkinson cycle cam 27.

  When switching from the Atkinson cycle to the rest mode, the hydraulic pressure is applied to the fourth hydraulic chamber 61, and the hydraulic pressure is released from the second hydraulic chamber 52 with the engagement pin 62a abutting against the outer periphery of the first connecting pin 41. Hydraulic pressure is applied to the first hydraulic chamber 51. Then, as shown in FIG. 2, the engaging pin 62a engages with the engaging groove 57 while the first connecting pin 41 moves to the second free rocker arm 20 side by the hydraulic pressure of the first hydraulic chamber 51, and the first connecting pin 41 is engaged. The pin 41 is held at a position for releasing the connection between the drive rocker arm 18 and the first free rocker arm 19. In this state, the drive rocker arm 18 is not connected to any of the first to third free rocker arms 19 to 21, and the intake valves 13 are closed.

  When switching from the middle load range normal cycle to the pause mode, the hydraulic pressure is applied to the fourth hydraulic chamber 61, and the hydraulic pressure is applied from the first hydraulic chamber 51 with the engagement pin 62a abutting against the outer periphery of the first connecting pin 41. The hydraulic pressure is applied to the second hydraulic chamber 52 while being released. Then, the engagement pin 62a is engaged with the engagement groove 57 while the first connection pin 41 is moved to the first free rocker arm 19 side by the hydraulic pressure of the second hydraulic chamber 52, and the first connection pin 41 is connected to the drive rocker arm 18 and The first free rocker arm 19 is held at a position to release the connection, and the intake valves 13 are in a closed valve closed state.

  By the way, the drive rocker arm 18 linked and connected to the intake valves 13 is urged so as to be always slidably contacted with the rest cam 26 by the spring force of the valve springs 16 that urge the intake valves 13 to close. The spring force of the valve springs 16 does not reach the first to third free rocker arms 19 to 21 in a state where the connection with the drive rocker arm 18 is released. Therefore, the first to third free rocker arms 19 to 21 are urged by the lost motion mechanisms 94, 98, 99 so as to be in sliding contact with the corresponding cams 27, 28, 29.

  Referring to FIG. 1, an arm portion 19 a extending on the opposite side to the intake valve 13 is integrally provided at one end portion of the first free rocker arm 19, and the lost motion mechanism 94 includes the first roller 32. In order to urge the first free rocker arm 19 to the side to be brought into rolling contact with the Atkinson cycle cam 27, it is disposed above the arm portion 19a.

  The lost motion mechanism 94 is formed in a bottomed cylindrical shape released to the arm portion 19a side, is disposed above the arm portion 19a and is fixed to the cylinder head 11, and the arm portion 19a. A pressing member 96 that is formed in a bottomed cylindrical shape with its lower end closed so as to abut from above, and is slidably fitted to the housing 95, and is contracted between the housing 95 and the pressing member 96. And a lost motion spring 97.

  Thus, arm portions 20a and 21a extending on the opposite side to the intake valves 13 are integrally provided at one end portions of the second and third free rocker arms 20 and 21, and the lost motion mechanisms 98 and 99 are In order to bias the second and third free rocker arms 20, 21 to the side where the second and third rollers 34, 38 are brought into rolling contact with the medium load range normal cycle cam 28 and the high load range normal cycle cam 29, Arranged above 20a and 21a.

  Next, the operation of this embodiment will be described. The connection switching means 23 includes first and second connection pins 41 and 42, but the other end of the first connection pin 41 and the second connection pin 42 are provided. Since the oil passage 89 leading to the second hydraulic chamber 52 facing one end is formed in the second connecting pin 42, the oil passage 88 provided on the second free rocker arm 20 side and leading to the oil passage 89 is The rocker arms 18 to 21 constituting the valve operating device 17, the interfaces between the rocker arms 18 to 21, and the positions and shapes of the connecting pins 41 and 42, etc., may be disposed within the moving stroke of the second connecting pin 42. The degree of freedom in arrangement of the oil passage 88 provided in the second free rocker arm 20 can be increased while optimizing the equal configuration.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

  For example, in the above embodiment, the intake valve 13 has been described as an engine valve, but the present invention can also be implemented in connection with an exhaust valve.

FIG. 3 is a longitudinal side view of the valve gear, which is a cross-sectional view taken along line 1-1 of FIG. FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1 in a pause operation mode. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 1 in a pause operation mode. It is a figure which shows the change of the valve lift amount and the opening angle by the change of the operation mode. FIG. 3 is a cross-sectional view corresponding to FIG. 2 in a high load normal cycle operation mode. FIG. 3 is a cross-sectional view corresponding to FIG. 2 in a medium load normal cycle operation mode. FIG. 3 is a cross-sectional view corresponding to FIG. 2 in an Atkinson cycle operation mode.

Explanation of symbols

17 ... Valve operating device 18 ... Drive rocker arm 19 ... First free rocker arm 20 ... Second free rocker arm 21 ... Third free rocker arm 22 ... Camshaft 23 ... Connection switching means 26 ... Pause cam 27 ... Atkinson cycle cam 28 ... Medium load range normal cycle cam 29 ... High load range normal cycle cam 41 ... First connection pin 42 ... Second connection pin

Claims (1)

  A plurality of rocker arms (18, 19, 20, 21) arranged adjacent to each other with a common swing axis, and a plurality of cams (22) provided on the camshaft (22) individually corresponding to the rocker arms (18-21). 26, 27, 28, 29) and connection switching means (23) capable of changing the operation mode of the engine valve (13) by switching the combination of connection and release of the rocker arms (18 to 21). In the valve operating apparatus of the engine, the connection switching means (23) includes a plurality of connection pins (41) for switching connection and release of connection between adjacent rocker arms (18, 19, 20; 20, 21) according to the action of hydraulic pressure. 42), and in at least one of the connecting pins (42), an oil passage (89) communicating with the hydraulic chamber (52) facing the end of the connecting pin (42) is formed. A valve gear of an internal combustion engine characterized by.

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